I suspect this answer should be obvious, but I'm still fairly new at this...
My project requires me to, among other things, light up some LED illuminated buttons from an arduino duemilanove, and I'm concerned about the current they might draw from the board.
The LED lamps I'm using in each button are triple led clusters, seen here: http://www.happcontrols.com/pushbuttons/915wb61w.htm (#91-10WB-53W; 5-6v; white; triple led cluster; T 3-1/4)
I emailed the LED supplier for the specs, and they returned with this:
AXIAL LUMINOUS INTENSITY (IV) UNIT;MCD 1100 IF=20 MA DOMINANT WAVELENGTH UNIT NM X==0.29 Y= 0.30 IF=20MA VIEWING ANGLE 180 DEGREES POWER DISSAPATION MAX 300 MV CONTINUOUS FORWARD CURRENT 60 MA PEAK FORWARD CURRENT (1/10 DUTY CYCLE 0.01 MS PULSE WIDTH) 180 MA OPERATION TEMP RANGE -25 DEGREES C TO +85 DEGREES C
I know each arduino pin can output a max of 40mA, but I'm not quite sure what to make of some of these LED specs. I'm inclined to read those specs to mean that it operates normally at 20mA, which is good for me. The 60mA is the maximum the bulb withstand continuously, and 180mA is the maximum it can take when pulsed? But the bulb won't draw that much current unless it's supplied, correct? So... a single one of these should operate fine powered off a single pin? I just don't want to burn out my arduino.
The safe answer, I suppose, would be to use a transistor to switch each bulb indirectly, powering them all from the 5v pin. But it'd be nice to control things directly if safe.
Thanks in advance for any help!